- What CMR Means on This Site
- Who Issues the Credential
- How the Exam Works
- The Seven Exam Domains
- Eligibility and the Application
- Fees: Issuer Costs vs. Optional Spending
- Prescribed References
- Credentials That Share the Acronym
- Reading the Pass-Ratio Figure Carefully
- Staying Certified: Renewal
- Who Uses the Credential
- A Domain-Ordered Prep Sequence
- Frequently Asked Questions
- CMR here means Council-certified Microbial Remediator, issued by the American Council for Accredited Certification (ACAC), not any other credential sharing the...
- The exam is 100 multiple-choice questions in three hours, closed book, with a 75% passing criterion.
- ACAC publishes seven unweighted domains, so plan coverage across all of them rather than chasing percentages.
- The initial US/Canada fee is USD 500; the certification lasts two years and renews for USD 400.
What CMR Means on This Site
"CMR" is one of the most overloaded acronyms in professional credentialing. On this site, and throughout this article, CMR means Council-certified Microbial Remediator: a credential for people who plan, perform or supervise the remediation of microbial contamination, most commonly mold, in buildings. It is an applied, field-oriented certification. It is not a clinical, engineering-licensure or inspection credential.
If you are weighing whether this is the right credential for your career, our companion pieces approach the topic from different angles: what CMR stands for, what CMR certification involves, and the more detailed CMR eligibility and prerequisites breakdown. This page is the orientation piece: what the credential is, how it is structured, and how to decide on next steps.
Who Issues the Credential
The Council-certified Microbial Remediator designation is issued and administered by the American Council for Accredited Certification (ACAC). Certification decisions are made by ACAC's CMR Certification Board, which reviews each applicant after the examination stage. The board's review is unanimous, meaning passing the exam alone is not the final step. Your application file has to hold up as well.
Testing is delivered through Kryterion, Inc., the testing provider. ACAC's published materials also state that its CMR and CMRS credentials carry CESB accreditation. Note that CMRS (the supervisor-level sibling credential) has its own eligibility and exam details. Keep the two distinct when you read provider marketing, since some course pages bundle "CMR/CMRS" language together.
How the Exam Works
The CMR examination is a single, closed-book test with these characteristics:
- 100 multiple-choice questions, each with at least four answer choices.
- Three hours to complete the exam.
- 75% passing criterion, set by the certification board using a modified Angoff method, a standard-setting approach in which subject-matter experts judge how a minimally competent candidate would perform on each item. See our dedicated CMR passing score explainer for detail.
- Randomized question and answer order and immediate results at the end of the session.
- Two delivery modes: a testing center, or online with video proctoring.
Online candidates must supply their own computer, an approved webcam, a private location and a continuous 2 Mbps upload/download connection. Treat the technical requirements as part of your preparation: a failed equipment check on exam day costs you more than a missed practice session. For scheduling windows and deadlines, see CMR exam dates and scheduling.
If you want to feel the pace of 100 questions in three hours, the CMR practice test on our main site is a good way to rehearse. Roughly 1.8 minutes per question is generous for recall items but tight for scenario-based ones, so practice pacing early.
The Seven Exam Domains
ACAC's scope document (CMRS and CMR Examinations, approved February 21, 2024) lists seven domains. No percentage weights are published. The numbered subdomain columns in the chart are not weights either, so any site claiming "Domain X is 25% of the exam" for this credential is not drawing on an official source. For a deeper walkthrough, see our complete guide to all seven CMR content areas.
Domain 1: Principles & Equipment
The foundation: how microbial growth works, what conditions support it, and the tools used to control it.
- Moisture, nutrients and conditions that drive amplification
- Containment concepts and negative-air strategies
- Filtration, air-scrubbing and drying equipment and how each is applied
Domain 2: Guidelines, Regulations & Standards
Knowing which document governs which decision. The ACAC Code of Conduct sits within this domain rather than forming a separate one.
- Industry guidance and consensus standards, including edition awareness
- Professional conduct and scope-of-work boundaries
- How published guidance informs remediation protocol choices
Domain 3: Water Damage
Most mold problems begin with uncontrolled moisture, so water-loss knowledge is tested as its own domain.
- Categories and classes of water loss and what they imply for response
- Structural drying principles and monitoring
- Deciding what can be dried in place versus removed
Domain 4: Structural and Contents Remediation
The hands-on core: removing, cleaning and verifying building materials and personal property.
- Removal versus cleaning decisions for porous, semi-porous and non-porous materials
- Containment setup, demolition and cleaning sequences
- Contents evaluation, handling and cleaning approaches
Domain 5: HVAC System Remediation
Air-handling systems can spread contamination building-wide, and they require their own protocols.
- Recognizing contaminated system components
- Isolation and cleaning approaches for ducts and equipment
- Preventing cross-contamination during work
Domain 6: Project Documentation & Verification
Remediation work that cannot be demonstrated is hard to defend.
- Scope-of-work records, photographs and logs
- Verification concepts and what "complete" means for a project
- Communication with owners, occupants and other professionals
Domain 7: Safety
Worker and occupant protection. Chemical safety and fall protection are tested here, not as additional domains.
- Respiratory protection selection logic
- Chemical hazard awareness for cleaning and biocidal products
- Fall protection and work-at-height awareness
The domain list tells you the exam rewards breadth tied to practice. Someone who has run containment jobs but never studied standards may be strong on Domain 4 and weak on Domain 2. For a candid assessment of where candidates struggle, see how hard the CMR exam is.
Eligibility and the Application
The CMR is an experience-gated credential. You cannot simply book a seat. ACAC recognizes two main pathways:
- Experience pathway: a high-school diploma or GED plus two years of documented microbial-remediation experience.
- Education pathway: a qualifying two-year postsecondary degree or equivalent 15 qualifying science-related credits, plus at least one year of relevant experience.
Accepted education fields include microbiology, engineering, science, architecture, industrial hygiene and related sciences. Full detail, including edge cases, lives in our CMR requirements guide.
What the application package contains
- The online application and an electronic affidavit.
- Four project sheets documenting your remediation work.
- Applicable education transcripts, if you are using the education pathway.
- Required email verifications; the handbook also requests employer affidavits.
After the exam, the certification board reviews the file. A prep course is optional; ACAC does not require it for the credential.
Certification versus licensing-only examination use
ACAC's exam is also used by some state licensing programs. Passing a licensing-only examination does not by itself confer the CMR designation. If your goal is the Council-certified Microbial Remediator credential, make sure you are applying through the certification route.
Fees: Issuer Costs vs. Optional Spending
It helps to separate what ACAC charges from what you may choose to spend on preparation.
| Item | Amount | Notes |
|---|---|---|
| Initial fee (US/Canada) | USD 500 | USD 100 examination plus USD 400 certification for the first two-year term |
| Outside US/Canada | USD 525 | Quoted on the current official application |
| Retake | USD 100 | Examination retake fee |
| Renewal | USD 400 | Per two-year term |
| Processing component | USD 100 | Part of the certification fee; non-refundable |
| Prep courses, reference books | Varies | Optional and priced by third parties |
For the complete picture, including how to budget for reference texts and optional training, see the CMR certification cost breakdown. If you are weighing the spend against career outcomes, our ROI analysis walks through the reasoning without assuming a guaranteed pay bump.
Prescribed References
ACAC's handbook assumes comprehensive knowledge of a set of prescribed texts. Its selected study pages are examples, not exhaustive coverage. The reference list includes:
- AIHA, Recognition, Evaluation & Control of Indoor Mold, second edition (2020)
- EPA, Mold Remediation in Schools and Commercial Buildings (2001)
- ANSI/IICRC S500-2021 (water damage restoration)
- ANSI/IICRC S520-2015 with R520-2015, or S520-2024 (mold remediation)
- NIOSH, Respirator Selection Logic (2004)
Edition matters. Standards are revised, and a question may reflect the edition ACAC prescribes rather than the newest one on the market. Note that some entries on ACAC's shared reference page, such as OSHA bibliography items, apply only to CMRS and are not part of the CMR list. Our CMR study guide maps these texts to the domains above.
Credentials That Share the Acronym
Search results for "CMR" mix unrelated credentials and job titles. Here is how to tell the neighbors apart from this one:
| Credential or term | Relationship to ACAC's CMR |
|---|---|
| CMRS (ACAC) | Sibling credential for supervisors; separate eligibility and exam details |
| NORMI Certified Mold Remediator | Separately issued by another organization; NORMI's syllabus and rules do not define the ACAC exam |
| IICRC AMRT | Different issuer and program; compare scopes before assuming equivalence |
| Unrelated "CMR" titles in other fields | Not connected; ignore their fees, dates and salary figures |
When a pass-rate, fee or salary figure turns up in a search result, check which "CMR" it is describing. Mixing them is the most common way candidates end up with wrong expectations.
Reading the Pass-Ratio Figure Carefully
ACAC's 2025 exam pass-ratio report shows 31%, from 4 passes in 13 examinations. That is a real, dated, issuer-published figure, but it should be read with caution:
- The cohort is tiny; a few candidates either way moves the percentage dramatically.
- The report includes retakes and state-licensing-only examinations, so it is not a first-attempt success probability.
- It cannot predict your own outcome. Preparation, experience and domain familiarity vary widely.
Key Takeaway
Use the 31% (4 of 13) figure as a signal that the exam is not a formality, not as a forecast. Our CMR pass rate analysis explains the limits of the data in more depth.
Staying Certified: Renewal
The certification is valid for two years, and renewal costs USD 400. Under ACAC's current procedures, renewal requires 40 RCs (renewal credits), allocated as:
- 10 for continued field activity, and
- 30 professional-development hours.
Keep supporting documentation, because it is requested on audit. Start a renewal folder the day you are certified: course certificates, project summaries and dated records are much easier to collect as you go than to reconstruct later.
Who Uses the Credential
Typical holders work in roles where remediation scope, documentation and safety decisions carry professional weight: remediation contractors, project managers and supervisors, restoration and water-damage firms, and consultants who write or review remediation protocols. Employers and clients may value a recognized third-party credential when bidding or documenting work, but the strength of that preference varies by market and employer.
We deliberately avoid quoting a salary number for the credential. No published source we reviewed isolates a certification-caused pay premium, and compensation depends on role, region and experience. For a sober treatment of earnings evidence and how to evaluate job postings, see the CMR salary guide and browse CMR jobs for the kinds of roles that mention the credential.
A Domain-Ordered Prep Sequence
Because ACAC publishes no weights, a sensible plan covers all seven domains and sequences them by dependency. Here is one example ordering for a multi-week effort, built around how the topics build on each other:
Foundations: Domains 1 and 2
- Read the AIHA and EPA texts for principles and terminology
- Note which standard governs which decision, and which edition ACAC prescribes
Moisture and materials: Domains 3 and 4
- Work through ANSI/IICRC S500 for water loss and S520 for remediation
- Practice material-by-material remove-or-clean decisions
Systems and records: Domains 5 and 6
- Study HVAC isolation and cleaning logic
- Draft a sample scope-of-work and verification log
Safety and full-length review: Domain 7 plus mixed practice
- Work NIOSH respirator selection logic until the steps are automatic
- Take timed, mixed-domain sets on the practice test site and revisit weak domains
Safety goes last in this ordering so it becomes the fresh, high-stakes lens through which you re-read everything else. For deeper plans and resource comparisons, see the CMR study guide, and keep the CMR cheat sheet handy for last-week review.
Frequently Asked Questions
Council-certified Microbial Remediator, a credential issued by the American Council for Accredited Certification (ACAC). It is unrelated to other credentials or job titles that use the same acronym.
The exam has 100 multiple-choice questions, a three-hour limit and a 75% passing criterion set by the certification board through a modified Angoff process. It is closed book, and results are immediate.
Yes. ACAC offers both testing-center delivery and online video-proctored delivery through Kryterion. Online candidates need a computer, an approved webcam, a private location and a continuous 2 Mbps upload/download connection.
No. A prep course is optional. You do need to meet the experience or education prerequisites, submit the application package (including four project sheets) and pass the exam. Courses and reference books are separate, optional costs.
It lasts two years. Renewal costs USD 400 and requires 40 RCs: 10 for continued field activity and 30 professional-development hours, with documentation available for audit. See the CMR certification overview for more.